Update dependency @ember/test-helpers to v2.9.4

Author: renovate[bot]

package.json

@@ -38,7 +38,7 @@
   "devDependencies": {
     "@ember/optional-features": "2.0.0",
     "@ember/string": "3.0.1",
-    "@ember/test-helpers": "2.9.3",
+    "@ember/test-helpers": "2.9.4",
     "@embroider/test-setup": "2.1.1",
     "@glimmer/component": "1.1.2",
     "@glimmer/tracking": "1.1.2",

yarn.lock

@@ -1072,10 +1072,10 @@
   dependencies:
     ember-cli-babel "^7.26.6"
 
-"@ember/[email protected].3":
-  version "2.9.3"
-  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.9.3.tgz#c2a9d6ab1c367af92cf1a334f97eb19b8e06e6e1"
-  integrity sha512-ejVg4Dj+G/6zyLvQsYOvmGiOLU6AS94tY4ClaO1E2oVvjjtVJIRmVLFN61I+DuyBg9hS3cFoPjQRTZB9MRIbxQ==
+"@ember/[email protected].4":
+  version "2.9.4"
+  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.9.4.tgz#985022e9ba05cfc918bcf08b77cbb355f85b723e"
+  integrity sha512-z+Qs1NYWyIVDmrY6WdmOS5mdG1lJ5CFfzh6dRhLfs9lq45deDaDrVNcaCYhnNeJZTvUBK2XR2SvPcZm0RloXdA==
   dependencies:
     "@ember/test-waiters" "^3.0.0"
     "@embroider/macros" "^1.10.0"